Draft control and fly ash separator



June 10, 1941. c BIRD 2,244,936

DRAFT CONTROL AND FLY ASH SEPARA'I'OR Filed March 4, 1940 INVENTORmar/:5 B/rd ATTORNEY Patented June 10, i941 UNITED STATES PATENT OFFICEI 2,244,936 DRAFT CONTROL AND ASH SEPARATQR Charles Bird, Dayton, OhioApplication March 4, 1940, Serial N0. 322,053 I 2 Claims.

This invention relates to admit control and fly ash separatorfor'furnaces and is designed more particularly for use with 'a stokerfed domestic furnace. A stoker fed furnace is usually provided withmeans, such as a motor driven fan, for producing a forced draft throughthe fire bed while the fuel is being fed thereto. The forced draft isdiscontinued when the feeding of the fuel is interrupted, the fan motorbeing stopped when the stoker is stopped or .shortly thereafter. Duringthe. intervals between fuel feeding operations it is desirable not onlythat the forced draft be discontinued but that the natural draft beinterrupted. Various devices have been provided for automaticallyinterrupting the natural draft when the forced'draft is discontinued butthese devices have been more or less unsatisfactory in their operationand effect, and, inasmuch as the most of them' at least required a;damper controlled opening in the smoke pipe, the opening of thedamper-permitting loose fly. ash to escape from the smoke'pipe into thefurnaceroom, from which it would find its way into the livingroom andother parts of the house.

One object of the invention is to provide a draft control which willoperate automatically WithOllt' the use of moving parts to eifectpractically complete, interruption of the natural draft when the forced'draftis discontinued.

A further object of the invention is to provide a draft control of sucha character that it will prevent the escape ofloose fly ash into thefurnace room at all times'.

To this end it is a further object of the invention to provide" meansfor separating at least a substantial part of the fly ash from the products of combustion passing through the smoke pipe and deposit the sameat a given point exteriorly of the smoke pipe.

Other objects of the invention may appear as the device is described indetail.

In the accompanying drawing Fig. 1 is a longitudinal sectional viewtaken vertically of a draft control embodying my invention; and Fig. 2is a transverse section taken on the line 2-2 of Fig. 1, looking in thedirection of the arrows.

In the drawing I have, for the purpose of illustration, shown thepreferred form of my draft control and fly ash separator but it will beunderstood that the apparatus may take various forms Without departingfrom the spirit of the invention.

As illustrated, the apparatus comprises a casing 5 which is here shownas rectangular in shape but. may be of any suitable form. At itsopposite ends the casing is provided with an inlet 8 and an outlet 1,the inlet and outlet being preferably'in the form of nipples mounted inthe walls of the casing and adapted for connection with the respectiveparts ofthe smoke pipe 8, the inlet nipple 6 being of course connectedwith that portion of the smoke pipe which leads from the furnace and theoutlet nipple 1 being connected with that portion of. the smokepipewhich leads to the stack. Mounted in the casing between the inlet andthe outlet is a stationary 132.1116 9 which is arranged between theinlet and the outlet, which are preferably in alinement one with theother, and'is of such an area. that it will extend across the inlet andbeyond all sides of the latter, but the area of the baflle is lessthanthe cross sectional area of the casing and it is so mounted. that itsedgesare spaced from the walls of the casing on all four sides of thebafile. The baflle may take any suitable form and is preferably mountedin an upright or substantially vertical position. In the form shown, itis rectangular inshape and comprises a vertical lower portion Ill and aforwardly inclined upper portion I l, the lower portion l0 beingprovided at its lower edge with a rearwardly extend ing horizontalflange l2. ,In the arrangement shown,.the baffie is supported on theside walls of the casing by transverse straps or bars 13 which areriveted or otherwise rigidly securedto the walls of the casing. "Thecasing is provided in its bottom wall, directly below the baflle, withan air inlet which preferably is in the form ofja pipe I4extendingjthrough the. bottom wall and downwardly a substantial distancebelow the casing, usually to a point nearthe floor of the furnace room,this pipe being of a cross sectional areav approximating equal to thecross sectional area of the smoke pipe. Mounted in the air, inlet pipe14 is a normally stationary butjadjustable damper [5 which is here shownas anio'r'dinaryv butterfly damper.

When a forced draft is being passed through the fire bed the products ofcombustion enter the casing through the inlet 6, passing about the edgesof the baffle to the outlet 1 and thence to the stack. The arrangementof the bafile is preferably such that the major portion of the productsof combustion passes about the upper and side edges of the baffle and,in the present arrangement, the inclined upper portion of the bafile andthe flange l2 tend to divert the gaseous products of combustion upwardlyso that only a relatively small portion of the same pass beneath thelower edge of the baffle. The quantity of the products of combustionwhich pass below the lower edge of the bafile is not sumcient to drawany large amount of air through the pipe l4 and so far .as the'operationof the device is con-j cerned it is immaterial whether or not air entersthe casing through that pipe, during the operation of the forced draft.However, more or less air will be drawn through the pipe l4 and thearrangement of the baffle is suchthat the cool air which thus entersthecasing will pass at least partly across the back of the baffle and willtend to cool the latter and thereby reduce the in-l jurious effect ofthe products of combustion on' the baffle. Further than this theairwillmerelyn serve to more completely fill the outlet portionterrupted the natural draft in the stack-will draw air through the airinlet pipe [Leasing H 5 and smoke pipe 8 to the stack, in such quan-'tities as are required by the natural draft. As a 'result" the flowofair-or productsfof combustion from thefurriace to thecasing 5ispractical- 1y interrupted, thus'alm'o'st entirely if notentirely'eliminating draft through the fire bed. The damper l5 is'adjusted inaccordance'with the. requirements of the furnace and stack of eachinstallation and, after having been'adjusted,'remains stationary duringthe operation 'of theiap'paratus. v

As the products of combustion enter the casing s'dunng the forced draft'period' they impinge against the baffle 9 and a substantial amount ofthe fly ash or. other-solids'are separated from the gases and fall bygravity through the lower portion of the casing to the air inlet pipeHLwhich then constitutes a discharge'conduit for the'sep- 'arated'matter. The separatedmatter as. here shown is rather coarse but.usuallyfthis matter consists" 'm'ostly, if notentirely'of fly ash whichis of a very'fine'powder'ed nature; The'solids'may be discharged. fromthe pipe I 4 onto the floor of the Ifurnace roomfor into a receptacle'16 placed beneath the'pipe,'but in either, casein'o loosefash willbet-permitted to escape into theatm'osphere ofthe furnace room; "Unlessthe discharged ash is permitted to' pile up very close to the lower endof the pipe Is the now of air through that pipe, when thelforced drafthas been'discontinued, will not carry any part of the ash'into the pipe,but should it do so this ash will merely pass out throughthe stack andnoharmwill' be done.

iIt. will be apparent therefore that I have providediin the presentapparatus a draft control which" automatically effects, substantiallycompleteiinterruption of the natural draft through the fire bedduringthe intervals betweenjfuel feeding'operations,when the forced draft hasbeen discontinued, and means for preventing the escape of loose fly ashfrom the draft controliap paratus into the furnace room. Theconstruction is very simple but is highly efi'icientin its opera tionand can be easily installed in the smoke pipe of the furnace.Preferablythe' overall length of the apparatus, including the inlet andoutlet nipples 6 and I, would be equal to the standard length of asection of smoke pipe so that this apparatus could be substituted for aremoved section of smoke pipe.

While I have shown and described one embodiment of my invention I wishit to be understood that I do not desire to be limited to the detailsthereof as various modifications may occur to a person skilled in theart.

Having now fully described my invention, what I claim as new and desireto secure by Letters Patent, is: 1. A draft control and ash separatorfor a furnace of the type having intermittently operating mea ns forcreating a forced draft through the fire bed and having a smoke pipeleading to a-stack, comprising a casing having an inlet and an outlet onopposite sides thereof adapted to be and spaced from said outlet, saidbaffle extending transversely beyond said inlet in all-directions andhaving its several edges spaced from the adjacent walls of said casingto intercept'the' solid products of combustion while permittinga'substantially unrestricted flow of gaseous products of combustionabout said spaced edges tosaid outlet under forced draft, and aconstantly open passageway communicating with thelower portion of saidcasing throughfwhich'the intercepted solids are discharged and soarranged that upon the discontinuance of the forced draft the naturaldraft in the stack will draw air through said passage wayandisubstantially eliminate draftthrough saidfirebed. V l .7

2. A draft control and ash separator for a' furnace of the type havingintermittently operating I means for creating a forced draft through thefire bed and having a smoke pipe leading to a stack, comprising a casinghaving an inlet and an outlet on opposite sides thereof, substantiallyin line one withthe other and adapted to be connected re spectively withthe furnace and the stack, a stationary baflie mounted in saidcasingbetw'een and in spaced relation to said inlet and said outlet andhaving its upper portion inclined upwardly to} ward the outlet wall ofsaid casing, said bafile e5:- tending transversely beyond all edges ofsaid inlet and having its several'edges spaced from the ad jacent wallsof said casing to intercept solid prod: ucts of combustion while'permitting a substantially unrestricted flow of gaseous products ofcombustion about saided'ges to said outlet under forced draft, and aconstantly open'conduit cornmunicating with'said casing below saidbafile and extending downwardly therefrom to receive the interceptedsolids and so arranged that upon discontinuance of the forceddraftthenatural-draft of the stack will draw' air through" saidpassageway and substantially eliminate all {draft from thefirebowl. I

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